▎ 摘　　要

NOVELTY - The heat radiation material has a heat radiation layer (12) consisting of a graphene layer (16) and a nanotube shaped layer (17) formed on the surface of an insulating substrate (11). The graphene layer has a crystallography (c) axis perpendicular to the substrate surface. The nanotube shaped layer has nanotubes having a length direction oriented in a direction perpendicular to substrate surface. A catalyst layer (18) consisting of material selected from a group including iron (Fe), nickel (Ni) and cobalt (Co) is formed between graphene layer and nanotube shaped layer. USE - Heat radiation material for flexible printed circuit board. ADVANTAGE - The heat dissipation is improved by using the heat radiation layer having high heat conductivity in the direction parallel to substrate surface and in the direction perpendicular to substrate surface. DETAILED DESCRIPTION - An INDEPENDENT CLAIM is included for printed circuit board manufacturing method. DESCRIPTION OF DRAWING(S) - The drawing shows the sectional view of the flexible printed circuit board. Flexible printed circuit board (10) Substrate (11) Heat radiation layer (12) Graphene layer (16) Nanotube shaped layer (17) Catalyst layer (18)